Gertrude and Claudius is a novel by John Updike. It uses the known sources of Shakespeare's Hamlet to tell a story that draws on a rather straightforward revenge tale in the medieval Denmark depicted by Saxo Grammaticus in his twelfth-century Historiae Danicae, but incorporates extra plot elements added by François de Belleforest in his Histoires tragiques, published in 1576. And, finally, it brings in various elements from Shakespeare's play, including the name "Corambis" for Polonius from the "bad quarto" of 1603. This story, in its three forms, is primarily concerned with Hamlet (or "Amleth" in Saxo) avenging his father's murder, but the story starts earlier. The novel is concerned with that earlier life of Gertrude, Claudius, and old Hamlet, and it ends at the close of Act I, scene ii